A British postage stamp series commemorates the 50th anniversary of the “Doctor Who”show with a stamp for each of the 11 doctors from William Hartnell (pictured) from the 1960s and Matt Smith, the current doctor.

A British postage stamp series commemorates the 50th anniversary of the “Doctor Who”show with a stamp for each of the 11 doctors from William Hartnell (pictured) from the 1960s and Matt Smith, the current

A British postage stamp series commemorates the 50th anniversary of the “Doctor Who”show with a stamp for each of the 11 doctors from William Hartnell from the 1960s and Matt Smith (pictured), the current doctor.

A British postage stamp series commemorates the 50th anniversary of the “Doctor Who”show with a stamp for each of the 11 doctors from William Hartnell from the 1960s and Matt Smith (pictured), the current

The Daleks, “Who’s” most infamous monsters, first screamed “Exterminate!” in 1964.

The Daleks, “Who’s” most infamous monsters, first screamed “Exterminate!” in 1964.

Photo: Ronald Dumont, Getty Images

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“Doctor Who,” TV’s longest running science fiction series, celebrates a landmark this year — its 50th anniversary. As for the Doctor himself, played currently by Matt Smith, he clocks in at upward of 1,200 years old (as stated in the recent Western-themed episode “A Town Called Mercy”). Eleven Doctors have graced the series, thanks to the crafty introduction of regeneration, which allows the Doctor, upon death, to transform into a new body.

“Doctor Who,” TV’s longest running science fiction series, celebrates a landmark this year — its 50th anniversary. As for the Doctor himself, played currently by Matt Smith, he clocks in at upward of ... more

Photo: Harry Todd, Getty Images

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Patrick Troughton

(second from left), 1966-1969

Patrick Troughton

(second from left), 1966-1969

Photo: Keystone, Getty Images

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Jon Pertwee

was the third Doctor Who. He had the role from 1970 to 1974.

Jon Pertwee

was the third Doctor Who. He had the role from 1970 to 1974.

Photo: Evening Standard, Getty Images

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Tom Baker

played the Doctor from 1974 to 1981. He was the longest lasting and most eccentric Doctor who was known for his mile-long scarf, floppy hat and comical flair.

Tom Baker

played the Doctor from 1974 to 1981. He was the longest lasting and most eccentric Doctor who was known for his mile-long scarf, floppy hat and comical flair.

Photo: Anwar Hussein, Getty Images

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Peter Davison

was the fifth Doctor Who, in the early 1980s.

Peter Davison

was the fifth Doctor Who, in the early 1980s.

Photo: Gary Weaser, Getty Images

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Colin Baker

(left) played Doctor Who from 1984 to 86. He’s shown here with his assistant Peri, played by Nicola Bryant, and an unidentified character.

Colin Baker

(left) played Doctor Who from 1984 to 86. He’s shown here with his assistant Peri, played by Nicola Bryant, and an unidentified character.

Photo: Photoshot

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British actor Sylvester McCoy played the Doctor from 1987 to 1989.

British actor Sylvester McCoy played the Doctor from 1987 to 1989.

Photo: Photoshot

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The the British series was canceled in 1989. However, “Doctor Who” returned for one night in 1996 as a TV movie starring Paul McGann as the eighth Doctor.

The the British series was canceled in 1989. However, “Doctor Who” returned for one night in 1996 as a TV movie starring Paul McGann as the eighth Doctor.

Photo: BBC

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Billie Piper was Rose Tyler and Christopher Eccleston was Doctor Who in 2005.

Billie Piper was Rose Tyler and Christopher Eccleston was Doctor Who in 2005.

Photo: SCI FI

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David Tennant

played Doctor Who from 2005 to 2010.

David Tennant

played Doctor Who from 2005 to 2010.

Photo: BBC Photo, SCI FI CHANNEL

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The fresh-faced, floppy-haired and bow-tied Matt Smith, 2010 to present, is the youngest actor ever to play the Doctor.

The fresh-faced, floppy-haired and bow-tied Matt Smith, 2010 to present, is the youngest actor ever to play the Doctor.

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Peter Capaldi, seen here at the June 2, 2013 world premiere of "World War Z" takes on the role of the 12th doctor starting in 2013. (Photo by Dave J Hogan/Getty Images)

Peter Capaldi, seen here at the June 2, 2013 world premiere of "World War Z" takes on the role of the 12th doctor starting in 2013. (Photo by Dave J Hogan/Getty Images)

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'Doctor Who' by the numbers

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This year, fans are making an especially big to-do over “Doctor Who.”

TV's longest running science fiction series celebrates a landmark — its 50th anniversary — and all kinds of events are planned: conventions, TV tributes, even a new cookbook has been published with Who-themed recipes.

As for the Doctor himself, played currently by Matt Smith, he clocks in at upward of 1,200 years old (as stated in the recent Western-themed episode “A Town Called Mercy”). Yet, the fresh-faced, floppy-haired and bow-tied Smith — the youngest actor ever to play the Doctor — doesn't look a day over 30, which is his age in human years.

Starting at 7 p.m. Saturday on BBC America, we head into the second half of Season 7, which runs for eight weeks. Smith's Doctor will be joined by a fetching new companion, Clara (Jenna-Louise Coleman), who has multiple personas in different time periods. The creepiest of these, so far anyway, was as a Dalek, “Who's” most infamous monster, which first screamed “Exterminate!” in 1964.

In Saturday's episode, Clara and the Doctor meet again in modern-day London in a Wi-Fi-themed adventure that reveals a horrific side to this pervasive technology. They go on to battle ghosts and other monsters, including an evil alien aboard a Russian submarine in the year 1983.

More numbers! So how about having some fun with other figures as they relate to Britain's most-revered time traveling alien?

﻿11-23-1963: The day after one of the most infamous dates in U.S. history, when President John F. Kennedy was assassinated in Dallas, “Doctor Who” debuted on British television with crotchety, silver-haired William Hartnell in the lead. Though only 55 at the time, Hartnell looked more like someone's old college professor than a time-hopping adventurer. Nevertheless, he and his three companions — his granddaughter and two schoolteachers — traveled in the TARDIS, a time machine/spaceship that looks comically like a 1950s-style English police call box, and battled countless monsters across the universe.

11: The number of Doctors who have graced the series, thanks to the crafty introduction of regeneration, which allowed the Doctor, upon death, to transform into a new body. In 1966, Patrick Troughton, a younger actor with a Beatles haircut, took over. And nine more followed, including three in the newest incarnation of “Who”: Christopher Eccleston (2005), David Tennant (2005-2010) and Smith.

7: The number of seasons of the longest lasting and most eccentric Doctor, Tom Baker (1974-1981), who was known for his mile-long scarf, floppy hat and comical flair.

1989: The year the British series was canceled. However, “Doctor Who” returned for one night in 1996 as a TV movie starring Paul McGann as the eighth Doctor.

2: The number of full-fledged spinoffs. Both came from “Who's” revivalist Russell T. Davies: “Torchwood,” which debuted in 2006, running three seasons on BBC America and one on Starz, follows a small team of alien-hunters, led by Capt. Jack Harkness (John Barrowman). And “The Sarah Jane Adventures,” a children's series which bowed in 2007 and starred Elisabeth Sladen as Sarah Jane Smith, “Doctor Who's” longest-lasting female companion, who reappeared in several episodes of the new series. Fans were crushed when Sladen died in 2011.

3: The number of TV networks that have carried “Doctor Who” in the United States. PBS introduced it here, followed by Syfy and BBC America.

1.2 million: The record number of American “Doctor Who” viewers who tuned in to Smith's — and new show-runner Steven Moffat's — series premiere in April 2010, bringing BBC America its highest-rated telecast until then. (Those numbers have continued to grow.) That stellar season also brought two new companions, Amy (Karen Gillan) and Rory (Arthur Darvill), who were part of the Doctor's life for 21/2 seasons.

48: The approximate number of countries that currently air “Doctor Who.”

95: The number of recipes in “Dining With the Doctor: The Unauthorized Whovian Cookbook,” written by Chris-Rachael Oseland to coincide with the show's 50th anniversary. Available at www.Amazon.com, it contains dishes such as TARDIS Wellington, Slitheen Eggs and, of course, Fish Fingers and Custard, and draws strictly from the new “Doctor Who.” Fans of classic “Who” will be more satisfied with Gary Downie's 1985 edition, “The Doctor Who Cookbook,” which contains recipes submitted by talent involved with the original series.